Re: [xsl] Keys and select distinct - is that the solution ?

Subject: Re: [xsl] Keys and select distinct - is that the solution ?
From: "Christian Rasmussen" <byggemandbob@xxxxxxxxx>
Date: Sat, 3 Jun 2006 00:38:27 +0200
sorry I mean it is a one-to-many
- christian


On 6/3/06, Christian Rasmussen <byggemandbob@xxxxxxxxx> wrote:
First of all thanx to both of you for trying to help.
right now I am trying to apply your suggestions....

I am a quite newbie and I am not not sure I understand the muenchian
method,
but regarding your last statement Wendell Piez:

I believe it is a many to many relation:

If you look back on my input, you can see that the code 5 for instance
is listed two times in one of the structures (aka tables), and I have
to take that value and look it up somewhere else in the document (aka
another table) and return the value "Ajle".

That is a one to many....

well, I'll go work on those two other suggestions...

- Christian

On 6/3/06, Wendell Piez <wapiez@xxxxxxxxxxxxxxxx> wrote:
> Dear Christian,
>
> XSLT 2.0 has a distinct-values() function, which
> is useful for this kind of thing, along with its native grouping
constructs.
>
> In XSLT 1.0, it's a fairly standard grouping
> problem. Usually we de-duplicate a set of nodes
> by determining which members of the set are the
> first (in document order) with a given value. In
> your case, you have to decide whether the value
> you want to check is the code value, or the name
> (if they're in a strict one-to-one relation it
> doesn't matter, and the value is more convenient).
>
> Keys are a very convenient way to de-duplicate
> when your data set is large. You can use brute XPath if not.
>
> So:
>
> <xsl:key name="manure-type-codes" match="gr:ManureTypeCode"
>    use="."/>
>
> <xsl:key name="manure-type-names" match="gr:ManureTypeName"
>    use="../gr:ManureTypeCode"/>
>
> <xsl:template match="gr:ManureTypeCode">
>    <xsl:if test="generate-id() =
generate-id(key('manure-type-codes',.)[1])">
> <!-- tests true only if the ManureTypeCode is the first with this
value,
>           more or less the equivalent of 'select distinct' -->
>      <xsl:copy-of select="key('manure-type-names',.)"/>
>    </xsl:if>
> </xsl:template>
>
> If the codes and names are in a one-to-many or
> many-to-many relation, we have to think harder.
>
> I hope this helps!
> Wendell
>
> At 05:55 PM 6/2/2006, you wrote:
> >Hi experts,
> >
> >I've been struggling with a problem for several hours now, and I
> >cannot find the solution:
> >I have an XML document with a elements grouped in elements and
> >ManureTypeCodes and datavalues as siblings.
> >Then I have - somewhere else - in the document lookup information
> >(labels) for the codes.
> >These are grouped in elements of ManureTypeCodes and ManureTypeNames
> >
> >I want to create a template rule which matches the codes and looks up
> >the corresponding name and ONLY writes the
> >ManureTypeName out once! In RDBMS I would use something like select
> >distinct when selecting the codes, but I dont know what the right
> >approach is in XSLT.
> >
> >can someone please help.... on before hand thank you!
> >
> >my XML:
> ><eih>
> >    <!-- Codes and data  -->
> >    <eih:ManureTypeCollection>
> >        <eih:ManureTypeStructure>
> >            <gr:ManureTypeCode>5</gr:ManureTypeCode>
> >            <gr:ElementIdentifier>N</gr:ElementIdentifier>
> >            <gr:ElementQuantity>17.0</gr:ElementQuantity>
> >        </eih:ManureTypeStructure>
> >        <eih:ManureTypeStructure>
> >            <gr:ManureTypeCode>5</gr:ManureTypeCode>
> >            <gr:ElementIdentifier>P</gr:ElementIdentifier>
> >            <gr:ElementQuantity>0.6</gr:ElementQuantity>
> >        </eih:ManureTypeStructure>
> >        <eih:ManureTypeStructure>
> >            <gr:ManureTypeCode>4</gr:ManureTypeCode>
> >            <gr:ElementIdentifier>N</gr:ElementIdentifier>
> >            <gr:ElementQuantity>17.5</gr:ElementQuantity>
> >        </eih:ManureTypeStructure>
> >        <eih:ManureTypeStructure>
> >            <gr:ManureTypeCode>4</gr:ManureTypeCode>
> >            <gr:ElementIdentifier>P</gr:ElementIdentifier>
> >            <gr:ElementQuantity> 6.3</gr:ElementQuantity>
> >        </eih:ManureTypeStructure>
> >    </eih:ManureTypeCollection>
> >
> >    <!-- look up information for the codes -->
> >    <eih:XImanureTypeCollection>
> >        <eih:XImanureTypeStructure>
> >            <gr:ManureTypeCode>4</gr:ManureTypeCode>
> >            <gr:ManureTypeName>Fast gxdning</gr:ManureTypeName>
> >        </eih:XImanureTypeStructure>
> >        <eih:XImanureTypeStructure>
> >            <gr:ManureTypeCode>5</gr:ManureTypeCode>
> >            <gr:ManureTypeName>Ajle</gr:ManureTypeName>
> >        </eih:XImanureTypeStructure>
> >        <eih:XImanureTypeStructure>
> >    </eih:XImanureTypeCollection>
> ></eih>
> >
> >
> >best regards,
> >
> >Christian Rasmussen
> >Denmark

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